Device and method for paramertizable controlling

ABSTRACT

To increase parameterization of control devices which include several inputs and several outputs, all combinations of inputs do not have to be evaluated for determining an output value. The set point value of input states are set to an independent state value such that only those real values and set point values have to be compared in a comparative step. The set point value does not match the independent state value, allowing the runtime for determining the output state values to be reduced.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/EP2004/006532 which has anInternational filing date of Jun. 17, 2004, which designated the UnitedStates of America and which claims priority on German Patent Applicationnumber 03014878.7 filed Jun. 30, 2003, the entire contents of which arehereby incorporated herein by reference.

FIELD

The present invention generally relates to a control device. Forexample, it may relate to one having a plurality of inputs forrespectively receiving an input real value, a plurality of outputs forrespectively outputting a digital output value, a memory for storingsetpoint values relating to the inputs and outputs, and an allocator forallocating a digital output value to one of the digital outputs as afunction of a comparison of at least one of the input real values with acorresponding setpoint value. The present invention also generallyrelates to a corresponding method for controlling equipment.

BACKGROUND

In many applications of control technology, outputs Y_(j) are switchedon or off as a function of inputs X_(i). A control device is in thiscase characterized by the number of outputs j_(max) and the number ofinputs i_(max). With respectively two inputs and outputs, i.e. j_(max)=2and i_(max)=2, sixteen different states are in principle conceivable.Correspondingly for controllers with eighteen input and outputs, whichare widely used in control technology, more than 260,000 differentstates are already possible.

In equipment produced to date, all the inputs and outputs are evaluatedby programmed technology. This, however, presents the followingdisadvantages with an increasing number of inputs and outputs (IOs):There is a great need for ROM and RAM. Furthermore, the parameterizationtable which increases exponentially in size requires a very largeEEPROM, long reading times etc. The large number of states furthermorerequires very complex parameterization and entails very long runtimes.Especially for safety technology, the latter is a great problem asregards emergency stop reaction times and maximum test times for thesecond fault occurrence time.

A controller of this high complexity is known, for example, from Pilzunder the reference “PNOZ MULTI”. A large part of the logic is in thiscase embodied in hardware. This is correspondingly configuredextensively owing to redundancy and diversity, associated with an SFFlevel of more than 90% for the KAT4 safety standard. Two differentcontroller types are in this case used with different firmware. Thepurpose of this is that the faster controller carries out the controlfunctions and the slower controller is used for the monitoring.

U.S. Pat. No. 4,510,602 discloses a programmable logic device whichincludes a multiplicity of memory devices, instruction words and maskingwords being stored in each of these memory devices, the wordsrespectively including a multiplicity of bits. By way of a comparatorunit and a comparer unit, a comparison of a word found on a data bus iscarried out with an instruction word contained in a memory and a maskingword. The data bus is in this case connected to inputs and outputs ofthe device. Depending on a comparison carried out, a marker unit whichtransfers a marker signal to outputs of the device is activated by thecomparator unit. The individual bits of the instruction words and themasking words can take the digital states “1” and “0”.

U.S. Pat. No. 5,623,680 discloses a state machine, which includes amemory in which logic specifications are stored. The changes of theoutputs are determined by these logic specifications as a function ofpredetermined combinations of input parameters, and a change of statesis carried out as a function of stored logic states of the inputparameters. The state specifications are in this case formed by separate8-bit words and combined with an input vector by a logical ANDoperation. The input vectors are in this case undescribed andcharacterize that by that only a single state which is specified by afurther vector can determine a state transition.

For their part, the present Applicant sells safety equipment of theSiguard series on the market, which makes do with one firmware and onecontroller type, although master-slave operation is necessary in whichboth controllers execute all the control functions and therefore inprinciple require double the runtime compared with the aforementionedequipment. This is therefore compensated for by a high-performancealgorithm.

SUMMARY

It is an object of at least one embodiment of the present invention toprovide a less elaborate controller and a corresponding method forsafety technology.

According to at least one embodiment of the invention, an object may beachieved by a control device having a plurality of inputs forrespectively receiving an input real value, a plurality of outputs forrespectively outputting a digital output value, a memory for storingsetpoint values relating to the inputs and outputs, and an allocator forallocating a digital output value to one of the digital outputs as afunction of a comparison of at least one of the input real values with acorresponding setpoint value. An independence state value can be appliedto at least one of the setpoint values in the memory. Further, theallocation of a digital output value to one of the digital outputs canbe carried out by the allocator independently of the at least one inputreal value whose allocated setpoint value has the independence statevalue. The setpoint values respectively have one of the state values 1,0 and independence state value. In this way, for example, it is possibleto produce the binary states “TRUE” and “FALSE” as well as a state whichis insignificant for the output result.

At least one embodiment of the invention also relates to a method forcontrolling equipment by receiving a plurality of input real values,providing setpoint values relating to input and outputs, establishing adigital output value as a function of a comparison of at least one ofthe input real values with a corresponding one of the setpoint values,outputting the digital output value, applying an independence statevalue to at least one of the setpoint values, and establishing thedigital output value independently of the at least one input real valuewhose allocated setpoint value has the independence state value. Thesetpoint values respectively have one of the state values 1, 0 andindependence state value. In this way, for example, it is possible toproduce the binary states “TRUE” and “FALSE” as well as a state which isinsignificant for the output result.

In safety technology, the error susceptibility and verifiability of thealgorithm are of prime importance. If the computing outlay is reducedaccording to at least one embodiment of the invention, a reliablecontrol function can therefore be readily achieved in master-slaveoperation.

The control device according to at least one embodiment of the inventionmay include a first evaluator for converting input raw values intodigital input values for the further processing as input real values.This makes it possible, for example, to classify analog input signals asan active or inactive input.

A second evaluator may furthermore be provided in the control device,which is connected downstream of the first evaluator. This allows thedigital input values to be allocated to logical input states for thefurther processing as input real values.

Preferably, the setpoint values respectively have one of the statevalues 1, 0 and independence state value. In this way, for example, itis possible to produce the binary states “TRUE” and “FALSE” as well as astate which is insignificant for the output result.

A plurality of sets of setpoint values may be stored, for example,respectively for an output value or set of output values in the memory.In this way, a plurality of parameterizations can be storedsimultaneously in the equipment.

The control device according to at least one embodiment of the inventionmay have a safety instrument by which the equipment to be controlled canbe switched to a safety state. For example, it may be switched to thesafety state if the output real values deviate from the correspondingsetpoint values for more than a predetermined time. In a special exampleof this, the control device may include two controllers which bothexecute the algorithm and store all fulfilled parameterizations as wellas the output vector Y_(j) in binary form. These stored values arecompared in each cycle. If they deviate for a time which is longer thana predetermined maximum time, then the equipment to be controlled isswitched to a safe state.

The safety device may be optimized by checking the sets of setpointvalues with a check sum at fixed time intervals. In particular, asetpoint value matrix i.e. a fixed parameterization, which is stored inthe memory, may be secured by a cyclic CRC (cyclic redundancy check sum)and verified at fixed time intervals in order to discover errors in thematrix S or in the memory. In this way, a variable function can bechecked for errors straightforwardly.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be explained in moredetail with the aid of the appended drawings, in which:

FIG. 1 shows an outline flow chart of the preprocessing of the inputreal values; and

FIG. 2 shows a logic diagram for the allocation of output statesaccording to at least one embodiment of the invention.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

The example embodiments described in detail below represent preferredembodiments of the present invention.

The outputs Y of the control-safety equipment are the result of aswitching function H with input X:Y=H(X)

The input X, or the plurality of inputs X_(i), in this case mayrespectively have the following states independently of its/theirfunction: $X_{i} = \begin{matrix}{0\quad\left( {``{FALSE}"} \right)} & {{input}\quad{must}\quad{be}\quad{inactive}} \\{1\quad\left( {``{TRUE}"} \right)} & {{input}\quad{must}\quad{be}\quad{active}} \\{D\quad\left( {``{DONTCARE}"} \right)} & {{input}\quad{state}\quad{may}\quad{be}\quad{anything}}\end{matrix}$

In control technology, an active output state Y_(j) is generally reachedfor precisely one or very few input state vectors. For most of the inputstate vectors X_(i), the output or outputs are inactively configured.With uncorrelated inputs, i.e. inputs that do not affect one another,for example operating selector switch, muting, key switch or the like,there are usually at most j_(max) input state vectors for j_(max) activeoutputs Y_(j).

If the inputs are correlated, however, then:

Number of the active output states$Y_{j} < {\overset{j_{\max}}{\sum\limits_{1}}\left( {\prod Z_{i}} \right)}$

Here, Z_(i) corresponds to the number of correlations of the inputsX_(i). In the limiting case of uncorrelated inputs, Z=1 since the inputsare then only correlated with themselves.

The evaluation of the inputs is carried out in two stages according tothis example according to at least one embodiment of the invention, asindicated in FIG. 1. Raw input data R_(i), for example analog signals ordigital signals of any level, are first subjected to a physicalevaluation. Here, for example, the allocation X_(i)=1 is made when thecorresponding input is active, and X_(i)=0 when the input is inactive.

In a second step S2, the digital input values X_(i) are logicallyevaluated. Each input therefore has a function ID, for exampleID₁=ID_POWERBUTTON. A logical input state or function value F_(i) isassigned to each digital input value X_(i). In the example, F_(i)=1would apply if the power button has been actuated successfully, andF_(i)=0 would apply if the power button has not been actuated or has notbeen actuated successfully.

A logical allocation is carried out in the further step S3, each realvalue F_(i) being compared with a setpoint value S_(i). A correspondingoutput value Y_(j) results from this comparison. Preferably, thecontroller is configured so that n_(max) different parameterizations canbe stored in it. Thus, for all the n_(max) parameterizations, a set ofsetpoint values S_(i,n) is respectively stored. They have the valuesS_(i, n) 0 (“FALSE”) input must be inactive 1 (“TRUE”) input must beactive D (“DONTCARE”) input state may be anything

FIG. 2 shows a flow chart for determining the output states Y_(j). In aninitialization step S4, the number of the parameter set is put at n=1and the output value Y_(j) is put at zero. In a further step S5, thelogical input states F_(i) for each parameterization n are compared withthe allocated threshold value S_(i,n) (comparison operator “==”). Allthe comparisons are combined by the AND operator “&&”. If the overallresult of the comparisons is “TRUE”, then the respective output Y_(j)receives the value of the logic operation “Y_(j) OR Y_(j,n)”. In thiscase, Y_(j,n) corresponds to the value stored as a setpoint valuetogether with S_(i,n).

The comparison routine of step S5 is repeated n times according to stepS6. After this, the output value assignment is ended according to stepS7.

For each parameterization, the output Y_(j) with Y_(j,n)=1 may then beconnected up or activated. Otherwise, the respective output Y_(j) isinactive.

According to at least one embodiment of the invention, not every realvalue F_(i) is compared with the corresponding setpoint value S_(i,n) instep S5. Rather, a comparison is only carried out if the setpoint valueS_(i,n) does not have the value “D”. This can avoid a multiplicity ofcomparison operations. The total runtime for determining the outputstates is correspondingly reduced.

If the inputs are mutually independent, for example in the case ofparallel switches, then the number of parameterizations n_(max) is equalto the total number of outputs j_(max). If the inputs are dependent onone another, however, for example switches connected in series, then twoparameterizations may for example be necessary for one output.

In a specific example, eleven independent inputs are applied to thecontroller in order to control four outputs. Accordingly, four differentparameterizations must be stored in the controller.

Example embodiments being thus described, it will be obvious that thesame may be varied in many ways. Such variations are not to be regardedas a departure from the spirit and scope of the present invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

1. A control device, comprising: a plurality of inputs to respectivelyreceive an input real value; a plurality of outputs to respectivelyoutput a digital output value; a memory to store setpoint valuesrelating to the inputs and outputs; and an allocator to allocate adigital output value to one of the digital outputs as a function of acomparison of at least one of the input real values with a correspondingsetpoint value, the setpoint values respectively including one of thestate values 1, 0 and independence state value, applicable to at leastone of the setpoint values in the memory, and the allocation of adigital output value to one of the digital outputs being capable ofbeing carried out by the allocator independently of the at least oneinput real value whose allocated setpoint value includes theindependence state value.
 2. The control device as claimed in claim 1,further comprising a first evaluator for converting input raw valuesinto digital input values for the further processing as input realvalues.
 3. The control device as claimed in claim 2, further comprisinga second evaluator, connected downstream of the first, for allocatingthe digital input values to logical input states for the furtherprocessing as input real values.
 4. The control device as claimed inclaim 1, wherein a plurality of sets of setpoint values are respectivelybeing storable for an output value or set of output values in thememory.
 5. The control device as claimed in claim 1, further comprisinga safety instrument by which the equipment to be controlled can beswitched to a safety state.
 6. The control device as claimed in claim 5,wherein the safety instrument switches to the safety state if the inputreal values deviate from the corresponding setpoint values for more thana predetermined time.
 7. The control device as claimed in claim 5,wherein the sets of setpoint values are checked with a check sum atfixed time intervals.
 8. A method for controlling equipment, comprising:receiving a plurality of input real values; providing setpoint valuesrelating to inputs and outputs; establishing a digital output value as afunction of a comparison of at least one of the input real values with acorresponding one of the setpoint values; and outputting the digitaloutput value, an independence state value being applied to at least oneof the setpoint values, the digital output value being establishedindependently of the at least one input real value whose allocatedsetpoint value includes the independence state value, wherein thesetpoint values respectively include one of the state values 1, 0 andindependence state value.
 9. The method as claimed in claim 8, whereinthe reception of a plurality of input real values includes conversion ofinput raw values into digital input values for the further processing asinput real values.
 10. The method as claimed in claim 9, wherein thedigital input values are allocated to logical input states for thefurther processing.
 11. The method as claimed in claim 8, wherein aplurality of sets of setpoint values are respectively provided for anoutput value or set of output values.
 12. The method as claimed in claim8, wherein the equipment to be controlled is switched to the safetystate if the input real values deviate from the corresponding setpointvalues for more than a predetermined time.
 13. The method as claimed inclaim 8, wherein the setpoint values are checked with a check sum atfixed time intervals, and the equipment to be controlled is optionallyswitched to a safety state.
 14. (canceled)
 15. (canceled)
 16. Thecontrol device as claimed in claim 2, wherein a plurality of sets ofsetpoint values are respectively being storable for an output value orset of output values in the memory.
 17. The control device as claimed inclaim 3, wherein a plurality of sets of setpoint values are respectivelybeing storable for an output value or set of output values in thememory.
 18. The control device as claimed in claim 6, wherein the setsof setpoint values are checked with a check sum at fixed time intervals.19. The method as claimed in claims 9, wherein a plurality of sets ofsetpoint values are respectively provided for an output value or set ofoutput values.
 20. The method as claimed in claims 10, wherein aplurality of sets of setpoint values are respectively provided for anoutput value or set of output values.
 21. A control device, comprising:input means for respectively receiving an input real value; output meansfor respectively outputting a digital output value; memory means forstoring setpoint values relating to the inputs and outputs; andallocation means for allocating a digital output value to one of thedigital outputs as a function of a comparison of at least one of theinput real values with a corresponding setpoint value, the setpointvalues respectively including one of the state values 1, 0 andindependence state value, applicable to at least one of the setpointvalues in the memory means, and the allocation of a digital output valueto one of the digital outputs being capable of being carried out by theallocation means independently of the at least one input real valuewhose allocated setpoint value includes the independence state value.